Wildfires are one of the main threats to overhead power lines worldwide, causing permanent damages and interruptions. Wildfires represent the second leading cause of outages in the Brazilian Interconnected Grid and the fourth leading cause in the United States (US) bulk grid. It is estimated that 4.8 thousand momentary and permanent failures in the US bulk grid from 2008 to 2019 were caused by wildfires [1]. Among the operational impacts to the power grid, this particular type of event may result in significant physical damages, such as burning support structures and conductors and contamination of the insulation system. In addition, wildfires under conductors can cause the degradation of the insulation medium resulting in phase-to-ground and phase-to-phase wildfire-induced flashovers.Preventing transmission lines from fire-induced flashovers is a challenging task. While engineers have the opportunity to design new transmission lines to prevent this type of failure mode, modifying the clearance distances of existing lines may be economically unfeasible. Consequently, vegetation management, fire prevention campaigns, and firefighting strategies are the only options to prevent damage and line outages. The environment in which the asset is installed and the characteristics of the transmission line may impact the reliability of the installation in different ways, as the insulating performances of overhead transmission lines for steady-state and transient operating conditions are affected by the clearance distances adopted. Nevertheless, current overhead transmission line standards do not establish design or operation and maintenance protocols to evaluate and address risks, impacts, and mitigation methods of wildfire. This design shortcoming very often results in impacts on the grid. This research proposes a novel data-driven methodology to estimate the risks of wildfire and outage of overhead transmission lines (OHTLs) due to fire-induced flashovers. Publicly available remote sensing data and geoprocessing techniques are applied in a case study of a compact 500 kV OHTL installed in the Brazilian tropical savanna to estimate the risk of wildfire and the insulation performance of the OHTL. In addition, the research proposes an empirical model to determine the minimum vegetation clearance distance (MVCD) in order to prevent fire-induced flashovers in OHTL installed in that particular biome. The research evaluates the results of six different calculation methods and clearance distances of line spans identified in 108 wildfire-related outage events. The outcomes from this research may be used as decision-making tools for a) route optimization of new overhead transmission lines, identifying crossed regions with higher exposure to wildfires; b) determining minimum clearance distance for new transmission lines to prevent fire-induced flashover; and c) Vegetation management prioritization for existing assets, identifying and providing specific clearance distances to prevent critical spans from outage due to fire-induced flashovers as well as providing information for firefighting strategies.